1. Field of the Invention
The present invention relates to a software and hardware architecture for the loading and execution of test programs for automatic test equipment for testing circuits, such as integrated circuits or circuit boards. More particularly, the present invention relates to an object-oriented architecture for loading and managing test vectors and patterns of test vectors in a tester.
2. Background
Automatic test equipment for testing electronic circuits ("ATE testers" or, simply, "testers") normally operate under control of a program loaded in the tester itself and executing on the tester hardware. The test hardware generally includes an embedded computer that performs higher-level data management and control functions for the tester. An example of automatic test equipment in which the invention may be used is the system described in U.S. Pat. No. 5,212,443 to West et al. for Event Sequencer For Automatic Test Equipment ("West"), the disclosure of which is incorporated herein by this reference. A software architecture for the development and execution of test programs for such automatic test equipment is described in commonly-owned provisional U.S. patent application Ser. No. 60/003,010 for ATE TEST PROGRAMMING ARCHITECTURE, filed Aug. 31, 1995, the disclosure of which is incorporated herein by this reference.
A test vector is a cycle of operations that applies data to all the pins of the device under test at the same time. Vectors generally include opcodes, operands, and format data for each pin definition. A pattern is a sequence of test vectors. Test programs on a tester generally include large patterns of test vectors, which in the aggregate may exceed one gigabit of data. Consequently, a major challenge for automatic test equipment is the loading and management of test vectors of large size with speed and flexibility.